Method and apparatus for compacting flowable solids

ABSTRACT

The invention relates to a method and an apparatus for compacting flowable solids, in particular powders, flours or similar materials, preferably by packing in packagings or sacks. In order to increase the process reliability, there is provision for evacuation of the solid and its sack packaging to take place in a likewise evacuated environment.

The invention relates to a method for compacting flowable solids, inparticular powders, flours or like substances, preferably by packagingin packages or sacks, in accordance with the preamble of Claim 1.

The invention furthermore relates to an apparatus for compactingflowable solids.

In a process for the gravimetric dosing of bulk solids according toDE-C-19645505, a discharge apparatus is completely emptied, and thequantity of the bulk solids is determined and taken into account asblast. To that end, the discharge apparatus is run on empty at leastonce during the dosing process, the mass of the empty and the filleddischarge apparatus is weighed, and the difference represents the blastto be taken into account.

For such discharge apparatuses, a two-shaft discharge screw conveyer isknown, which has engaging spirals. The discharge screw conveyer is runwith negative pressure to avoid any impairment of the guide.

The bulk solids can be de-aerated by pressing or packing, i.e. withoutvacuum processing, and an expansion is possible after the pressing- orpacking element has been removed.

With a compacting method for flowable bulk solids according toEP-A-1561685, a compacting space is first filled with the bulk solidsand then the compacting space is decreased. Then the compacting space issealed gas-tight and subsequently increased again to generate a negativepressure. Then the compacted bulk solids flow out via an output opening.

WO-A-9007452 discloses a method for filling and evacuating largecontainers having a neck or a valve, for example for hygroscopicproducts, where the containers are filled in an evacuated chamber. Thevacuum can be adapted with the addition of inert gases.

The invention is based on the problem of developing a method forcompacting flowable solids, in particular powders, flours or likesubstances, preferably by packaging in packages or sacks, which allowsthe storage and transport of the compacted solids with little spacerequirements and stable positioning. Another goal is to reduce cost andincrease process reliability.

The storage times for the compacted solids may be very long.

The object of the invention is attained with the characteristics ofPatent claim 1. Because a storage chamber for a bulk solid as well as asack chamber is evacuated before or after filling, it is possible tocompact safely and to a high degree without any impairment to the flowproperties of the bulk solids during the bagging. The baggingpractically takes place as under “normal conditions.”

Preferred embodiments are disclosed in subordinate claims.

The compacting of white flour, for example, leads to an increase of theshelf life (no oxygen feed) and to a reduction of the packaged volume.Furthermore, it improves the stacking capability of the packagingcontainers and their handling and/or palletization. The growth ofinsects or mold as well as fatty oxidation is also inhibited.

The invention furthermore relates to an apparatus for compactingflowable solids, in particular powders, flours, or like substances,preferably by packaging into packages or sacks. The apparatus includes astorage chamber and a downstream sack chamber, both of which can beevacuated.

The vacuum is supposed to be formed as quickly as possible, if necessarywith pre-vacuuming.

Furthermore, filling can also be accomplished with tubular bags, with asack form means being used instead of a sack filler neck, and theproduct also being pre-weighed.

The apparatus in accordance with the invention for sacks as well astubular bags may be integrated at individual stations as well as incarousels. Furthermore, it is possible to perform an especiallyadvantageous staggered or preliminary vacuuming in carousels. Instead ofde-aeration, the negative pressure of a preceding station may be used.

The invention is described in the following embodiment in greater detailby means of an example. The illustration shows a principalrepresentation of the compacting apparatus.

The apparatus comprises a storage chamber 1 for flour or the like, witha sack chamber 2 located below and a slide 5 being arranged as shutoffmeans between the two chambers 1, 2, and with a sack filler neck 6 thatprojects into the sack chamber. Both chambers have a vacuum connection4. The storage chamber 1 furthermore has a fill opening that can besealed tightly with a lid 3.

At the neck 5 (sack filler neck), a sack to be filled (not shown) isattached in the usual manner.

Because an applied negative pressure already holds both chamberstogether, clamping elements are principally not required. They can bearranged for safety reasons, however.

Furthermore, certain elements (not shown) may be provided in the sackchamber 3 to lend the sack a specific form.

After the storage chamber 1 has been filled with flour for filling asack, and a sack has been provided in the sack chamber 2 and/or at theneck 6, both chambers 1, 2 are evacuated likewise via the vacuumconnection 4 while the lid 3 and the slide 5 are closed until sufficientnegative pressure has been reached. Then the clamping jaws at the neck 6are closed (the sack is attached) and the slide is opened until the sackhas been filled as desired. Then the slide is closed and the sack issealed airtight. Then both chambers 1, 2 are aerated to normal pressure,the clamping jaws at the neck are released, and the sack is moved out ofthe sack chamber 2 through an opening (not shown).

The neck 6 can be supplemented with a sack closing means. The storagechamber 1 has an upstream weighing and dosing means.

With a tightly closing slide 5, the storage chamber 1 alternately mayalso contain product for filling of a plurality of sacks, which meansthat the aeration and de-aeration effort can be reduced. To that end,the storage chamber 1 has a weighing- and dosing means.

REFERENCE SYMBOLS

1 Storage chamber

2 Sack chamber

3 Lid

4 Vacuum connection

5 Slide

6 Neck

1. Method for compacting flowable solids by evacuating the solids andbagging and/or packaging the solids in an evacuated container,characterized in that the evacuation of the solids and their bagging areperformed in similarly evacuated environment.
 2. Method in accordancewith claim 1, characterized in that the evacuation of the solids andtheir bagging is performed in separate chambers that are connectedair-tight to one another.
 3. Apparatus for compacting flowable solids byevacuating the solids and bagging and/or packaging the solids in anevacuated container, characterized in that the apparatus has a storagechamber (1) for the solids and a downstream sack chamber (2) for thebagging, and both chambers (1, 2) can be evacuated and connectedair-tight relative to one another.
 4. Apparatus in accordance with claim3, characterized in that a tightly sealing shutoff device is arrangedbetween both chambers (1, 2).